1. Field of the Invention
The present invention relates to an information processing equipment having a display unit, for example, a workstation or a personal computer. More particularly, it relates to an information processing equipment which has a display unit capable of multicolor display and which can select the number of colors to-be-displayed and the operating frequency of the display unit.
2. Description of the Related Art
In recent years, information processing equipment such as workstations and personal computers have become remarkably reduced in size. As a result, they tend to be used in a variety of aspects. They can be broadly classified into three types; the conventional desktop type, the laptop type which can reduce the space needed for installation, and the so-called notebook type which is small in size and is excellent in portability. Among thede types, the information processing equipment of the notebook type should desirably be operable for a long time even though it has a light weight for realizing the portability. Accordingly, an important problem is how to efficiently utilize electric power which can be charged in the built-in battery of the notebook type equipment. In order to solve this problem, various techniques have been contrived. One of them is disclosed in the official gazette of Japanese Patent Application Laid-open No. 27420/1991 entitled "PERSONAL COMPUTER".
With the proposed personal computer, when an input device such as keyboard has not been operated at all for a predetermined time period, the supply of electric power from a power source circuit to a display unit can be stopped. That is, in the absence of keying for the predetermined time period, it is decided that the personal computer is in an idle state in which it is not used or operated by the user thereof, and the display unit of comparatively high power dissipation has its power source turned OFF. Thus, wasteful power consumption is prevented.
When, in this manner, the superfluous power dissipation is avoided on the basis of the detection of the idle state, the operable or serviceable time period of the personal computer with the battery can be prolonged.
Since, however, the frequence of the idle state is low in a data input job or a document preparation job extending over a long time, the operation of saving the power dissipation is not effectively performed with the technique which utilizes the idle state as explained above. Therefore, it will be sometimes impossible to secure a sufficient operable time period. It is accordingly important to secure a longer operable time period even in a state in which the user is continually using or operating such an information processing equipment.